In medical treatment, it is often necessary/important to isolate a certain section of a limb from the remainder of the body of the animal (eg. human), to prevent it from contacting certain liquids (especially water), solvents, surfaces etc. For example, where the skin of a user's limb has been cut, grazed, burnt, bandaged, plastered etc., it is often necessary/desirable to prevent that area from being subjected to contact eg. with water or other liquids (or even gases).
Crude attempts at isolating such limb sections have been devised over time, the most common including the insertion of the limb section into a plastic bag, and then the positioning of an elastic or rubber band adjacent to the opening of the bag and extending around the perimeter of the limb. These crude systems are often inadequate in protecting the limb region from the ingress of moisture, gases etc. and are cumbersome to use. 
Bag systems for positioning around the hand or feet of a user are shown in FR 2252839, GB 2265314, WO 98/17340, U.S. Pat. No. 4,966,135 and WO 93/14730. However, each of these documents disclose cumbersome or ineffective sealing mechanisms for preventing the ingress of unwanted matter into the bag (especially water). In particular, systems that are based around an adhesive attachment of the bag to the user's limb are disclosed in GB 2265314 and WO 98/17340. FR 2252839 discloses a separate elastic band securing system which may easily be dislodged, and is of a “primitive” nature in effect. U.S. Pat. No. 4,966,135, WO 93/14730 and NZ 280249 all disclose arrangements that only apply a line of force at an opening to a bag or cell which would rapidly become ineffectual over time or with repeated use.